Comparison of the metabolic responses of trained Arabians and Thoroughbreds during high- and low-intensity exercise.

The research article explores the metabolic differences between Arabian and Thoroughbred horses during exercise. It found that Thoroughbreds typically had higher aerobic capacity and running speed, while Arabians showed great use of fat for energy.

Research Methodology

• The research was conducted with 5 Arabian and 5 Thoroughbred horses who were given identical diet and followed the same exercise program for 2 months prior to the testing.
• The horses undertook three treadmill trials, with at least 7 days between each test. This included an incremental test for determining aerobic capacity and lactate threshold, a single high-speed test for estimating maximum accumulated oxygen deficit, and a low-intensity, 90-minute test.
• During these trials, measurements including VO2max (maximum capacity of an individual’s body to transport and use oxygen during exercise), running speed, and lactate threshold were taken.

Findings

• The VO2max and running speed at VO2max were found to be higher in Thoroughbred horses than Arabians. For example, VO2max was 154ml/kg/min at 12.9m/s for Thoroughbreds while it was 129ml/kg/min at 11.8m/s for Arabians.
• Thoroughbreds also exhibited a longer total run time during the incremental test and higher values during the high-speed test.
• However, there was no significant difference between the two breeds regarding their lactate threshold, which refers to the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed.
• During low-intensity exercise, Arabians showed higher levels of free fatty acids (indicating greater use of fat for energy) and a lower respiratory exchange ratio compared to Thoroughbreds. This might reflect breed variation in muscle fiber types.

Conclusions

• The study concluded that significant metabolic differences were observed between Arabian and Thoroughbred horses under both high- and low-intensity exercise conditions.
• This research provides valuable insights into the effects of exercise intensity on the metabolic responses of two horse breeds, potentially informing tailored training and nutrition strategies.
• While it suggests breed variation in muscle fiber types, the researchers indicate that further studies are needed to understand the mechanisms behind the observed differences in energy metabolism during exercise.